The trucking industry has grown considerably over the years. In order to handle the increased volume and capacity demanded of the trucking industry, trailers have been lengthened and payloads have been increased. Longer trailers have resulted in wider turns and larger swept areas, particularly in the case of right hand turns. In many urban areas, the roads and terminals were designed for much smaller trailers. On many trailers having increased payloads, the axles have been spread apart for better weight distribution and to satisfy bridge laws. The spread axle configuration is conventionally seen on flatbed, drop deck trailers, and refrigerated (reefer) trailers because of the concentrated load conditions. The spread axle configuration offers another advantage in that it provides a smoother ride, more stable platform, and better handling compared with closed tandem trailers. However, the spread axle configuration includes several drawbacks. In particular, because the axles are spread up to about ten feet, maneuverability suffers. In addition, tire wear and maintenance costs are increased. As the turning radius and stress on the trailer increases, more pressure is put on wheel bearings and suspension components, and the tires are often forced to scuff on a road surface. Flatbed trailers and refrigerator trailers are generally the only types of trailers having sufficient structural support to withstand the stresses associated with the conventional spread axle configuration.
Because of the increased length of trailers and the use of spread axles, truckers often get into stressful situations. In addition, when the trailers travel over curbs or outside their proper lane, damage to property and personal injury often result. For example, trailers often damage sign posts and traffic lights, and by jumping the curb, the cargo within the trailer can break. Furthermore, a trailer jumping a curb can injure people standing on the curb.
Steering axles have been developed. In the case of cement mixing trucks and dump trucks, steering axles have been developed for providing a load bearing axle. A problem associated with many prior steering axles is encountered when backing up. The steering wheels will follow the wheels of a tow vehicle when the tow vehicle is moving in the forward direction. When the tow vehicle backs up, the steering wheels of the trailer turn the wrong way, thereby jackknifing the trailer and the tow vehicle. In order to maneuver certain cement mixing trucks and dump trucks, however, the steering axle must be lifted off the ground which defeats the purpose of having a load bearing axle. Previous attempts at trailer steering devices can be seen in U.S. Pat. No. 2,498,779 to Winchester, U.S. Pat. No. 4,405,147 to Horseman et al., and U.S. Pat. No. 4,463,966 to Stoddard, and U.S. Pat. No. 4,770,430 to Lange.